The Remote Desktop Services (RDS) role in Windows server requires appropriate client access licenses (CALs) to be installed in order to function properly, but there is a 120-day licensing grace period which begins when the role is installed. During this grace period, RDS will function without any CALs having been installed. This is to allow an organization to configure and test its RDS environment to ensure that everything works as expected before purchasing and installing CALs.
It is possible to reset this grace period, but please note: resetting the licensing grace period is not a substitute for purchasing and installing the required Remote Desktop CALs. The following steps should not be performed on a server that is in production.
To reset the RDS licensing grace period, perform the following steps:
- On the RD session host, launch Registry Editor (regedit) as an administrator.
- In regedit, browse to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM\GracePeriod.
- Within this registry key is a REG_BINARY entry whose name begins with the string L$RTMTIMEBOMB. (This is likely the only entry in this key.) The default permissions on this entry do not allow it to be modified or deleted; therefore, these permissions must be changed
- Right-click the GracePeriod folder in the left pane of regedit and select Permissions.
- In the permissions window that appears, select Administrators and assign this group Full Control permissions. Click OK to close the window.
- Right-click the L$RTMTIMEBOMB… registry entry and select Delete. Click Yes to confirm the deletion.
- Exit regedit.
- Reboot the RD session host server in order for the registry change to take effect.
You may confirm that the procedure was successful by using the RD Licensing Diagnoser tool from the Tools menu of Server Manager. Clients should now be able to connect to this session host without the applicable CALs. Again, this procedure is not intended to be a substitute for purchasing and installing Remote Desktop CALs and should only be performed in a non-production (i.e., test/lab) environment.